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This content will become publicly available on January 25, 2017

Title: Hybridization-controlled charge transfer and induced magnetism at correlated oxide interfaces

At interfaces between conventional materials, band bending and alignment are classically controlled by differences in electrochemical potential. Applying this concept to oxides in which interfaces can be polar and cations may adopt a mixed valence has led to the discovery of novel two-dimensional states between simple band insulators such as LaAlO3 and SrTiO3. However, many oxides have a more complex electronic structure, with charge, orbital and/or spin orders arising from strong Coulomb interactions at and between transition metal and oxygen ions. Such electronic correlations offer a rich playground to engineer functional interfaces but their compatibility with the classical band alignment picture remains an open question. Here we show that beyond differences in electron affinities and polar effects, a key parameter determining charge transfer at correlated oxide interfaces is the energy required to alter the covalence of the metal–oxygen bond. Using the perovskite nickelate (RNiO3) family as a template, we probe charge reconstruction at interfaces with gadolinium titanate GdTiO3. X-ray absorption spectroscopy shows that the charge transfer is thwarted by hybridization effects tuned by the rare-earth (R) size. Charge transfer results in an induced ferromagnetic-like state in the nickelate, exemplifying the potential of correlated interfaces to design novel phases. Furthermore, ourmore » work clarifies strategies to engineer two-dimensional systems through the control of both doping and covalence.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [4] ;  [5] ;  [4] ;  [4] ;  [6] ;  [7]
  1. Univ. Paris-Saclay, Palaiseau (France)
  2. Univ. Complutense Madrid, Madrid (Spain)
  3. Univ. Complutense Madrid, Madrid (Spain); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Helmholtz-Zentrum Berlin fur Materialen & Energie, Berlin (Germany)
  5. Helmholtz-Zentrum Berlin fur Materialen & Energie, Berlin (Germany); Ruhr-Univ. Bochum, Bochum (Germany)
  6. Synchrotron SOLEIL, Gif-sur-Yvette (France)
  7. Synchrotron SOLEIL, Gif-sur-Yvette (France); Sorbonne Univ., UPMC Univ. Paris, Paris (France)
Publication Date:
OSTI Identifier:
1266019
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Nature Physics
Additional Journal Information:
Journal Volume: 12; Journal Issue: 5; Journal ID: ISSN 1745-2473
Publisher:
Nature Publishing Group (NPG)
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE